Non-inferiority Study Comparing Salvage Pelvic Radiotherapy in 25 Fractions (62.5 Gy/25) Versus 20 Fractions (52.5 Gy/20) for Recurrent Prostate Cancer After Surgery.

Non-Inferiority Study Comparing Hypofractionated Post-Operative Salvage Radiotherapy Regimens: 45/62.5 Gy in 25 Fractions vs. 43/52.5 Gy in 20 Fractions for Grade 2+ GU or GI Toxicity (HYP-OP-RT)

Study Overview This research compares two types of post-operative salvage radiotherapy (SRT) for men with prostate cancer who have had surgery but show signs of recurrence (detectable PSA). The goal is to see if a shorter treatment schedule is as safe and effective as the standard schedule.

Why is this study important? After prostate surgery, cancer can return in up to 70-80% of high-risk patients. Radiotherapy helps control this, but the best way to deliver it-especially the number of sessions and whether to treat the pelvic area-is still being studied. Shorter treatments could mean less time in therapy and better quality of life, if such treatments are proven safe.

What is being compared?

Standard treatment (Arm A):

25 sessions (about 5 weeks) Prostate bed: 62.5 Gy Pelvis: 45 Gy

Shorter treatment (Arm B):

20 sessions (about 4 weeks) Prostate bed: 52.5 Gy Pelvis: 43 Gy

Both groups may also receive hormone therapy (ADT) for 6-24 months.

Main Goal To check if the shorter treatment causes no more side effects (urinary or bowel problems) than the standard treatment, while keeping cancer control similar.

Other Things to be Measured

Cancer control (PSA levels, spread of disease) Survival Quality of life (urinary, bowel, sexual health questionnaires)

Who can join?

Men who:

Had prostate surgery Have a detectable PSA (≥0.2 ng/mL) No distant metastasis Are in good general health (ECOG 0-2)

How long will the study last?

About 12 years total:

2 years to enroll patients 10 years of follow-up

Inclusion Criteria:

• Histologically confirmed prostate adenocarcinoma.
• Prior radical prostatectomy with detectable PSA (≥0.2 ng/mL).
• No evidence of distant metastasis (confirmed via bone scan and CT/MRI or TEP-PSMA if PSA is above 0.5 ng /ml).
• Patient with Nodal recurrence within the pelvis are eligible
• ECOG performance status 0-2.
• Age ≥ 18 years.
• Adequate baseline renal, hepatic, and hematologic function.

Exclusion Criteria:

• Prior pelvic radiotherapy.
• Macroscopic local relapse on imaging
• Presence of metastatic disease.
• Active inflammatory bowel disease or other GI conditions predisposing to radiation toxicity.
• Uncontrolled comorbidities affecting study participation.
• Prior systemic therapy for recurrent prostate cancer (except ADT within 6 months).